Last week we were at WDW and decided to not buy G+ at MK (Monday 8/28) nor AK (Thurs 8/31) but did buy it for DHS (Wed 8/30 - $20) and EPCOT (Friday 9/1 - $17)
For MK, we were there from early entry through park close and got on 20 attractions. Dd 7DMT during early entry (~35min wait) and had longish waits for Space Mtn (57 mins) and Speedway (40mins) that were both well more than posted time. Everything else was under 30 mins, most under 20
For AK we got on everything we wanted and did Pandora mid-afternoon, had 23 min wait for FoP. Only other longish wait was for Kali River which was 30 mins despite a 5 minute posted wait time
For DHS and EP we "slept in a stacked" - we did get to DHS until around 12:30pm. Using LL we got on basically everything we wanted and did Rise standby (28 min wait to first preshow) - several we really didn't need, but did avoid like 25-35 min waits at things like MMRR, MF:SR, etc. Also helped having one for SDD when it closed for rain so got an anytime return one
EPCOT we were able to get one for Remy at 7, then Frozen after scanning in there and then TT after scanning in at Frozen, had them all done by noon. Really didn't need it for anything else, but saving 40+min for each of the 3 big ones was good
I think it is worth it if you want to sleep in or take breaks, but if you will be there from opening to close or don't care if you don't get on everything, definitely can do without